Transcript for Guido van Rossum: Python

Ouch, I did not expect such a deep one. I guess we all have good and evil potential in us and a lot of it depends on circumstances and context.

Well, as a teenager, my favorite writer was my favorite Dutch author was a guy named Villem Friedrich Hermons. who's writing certainly his early novels were all about sort of ambiguous things that happened during World War II. I think he was a young adult during that time and he wrote about it a lot and very interesting, very good books I thought.

No, it was all fiction, but it was very much set in the ambiguous world of resistance against the Germans, where often you couldn't tell whether someone It was truly in the resistance or really a spy for the Germans and some of the characters in his novels sort of crossed that line and you never really find out what exactly happened.

It's no, his heroes are often more, his main characters are often anti-heroes. And so they're not very heroic. They fail at some level to accomplish their lofty goals.

I still read novels. I don't think that it impacts me that much directly.

It's a separate world. My work is highly technical and the world of art and literature doesn't really directly have any bearing on it.

I'm not disagreeing with that. I'm just saying that sort of, I don't feel direct influences from more traditional art on my own creativity.

I think it was more the latter actually. I... Maybe towards the end of my high school period, I felt confident enough that I designed my own circuits that were sort of interesting. somewhat. But a lot of that time, I literally just took a model kit and followed the instructions, putting the things together. I mean, that I think the first few years that I built electronics kits, I really did not have enough understanding of sort of electronics to really understand what I was doing. I mean, I could debug it and I could sort of follow the instructions very carefully. which has always stayed with me, but I had a very naive model of how a transistor works. And I didn't think that in those days I had any understanding of corals and capacitors, which actually was a major problem when I started to build more complex digital circuits because it was unaware of the sort of the analog part of the how they actually work and I would have things that the schematic looked everything looked fine and it didn't work and what I didn't realize was that there was some megahertz level oscillation that was throwing the circuit off because I had a

No, I had no clue. I remember I think in the summer after my senior year, oh, maybe it was the summer after my junior year. Well, at some point I think when I was 18, I went on a trip to the math Olympiad in Eastern Europe. And there was like, I was part of the Dutch team. And there were other nerdy kids that sort of had different experiences and one of them told me about this amazing thing called a computer and I had never heard that word my my own explorations in electronics were sort of about very simple digital circuits and I I had sort of I had the idea that I somewhat understood how a digital calculator worked and so there is maybe Some echoes of computers there, but I didn't, I never made that connection. I didn't know that when my parents were paying for magazine subscriptions using punched cards, that there was something called a computer that was involved at the Red House cards and transferred money between accounts. I was also not really interested in those things. It was only when I went to university to study math that I found out that they had a computer and students were allowed to use it.

What did I feel like? That was the only thing you could do with it. The computer wasn't really connected to the real world. The only thing you could do was sort of you typed your program on a bunch of punched cards. You gave the punched cards to the operator and our later the operator gave you back your printout. And so all you could do was write a program that did something very abstract and I don't even remember what my first four days into programming were but they were sort of doing simple math exercises and just to learn how a programming language worked.

I don't think I really saw it that way. I was really more interested in the tinkering. It may be not as sort of a complete coincidence that I ended up sort of Creating a programming language which is a tool for other programmers. I've always been very focused on the sort of activity of programming itself and not so much what happens with the program you write. I do remember and I don't remember. Maybe in my second or third year I'll probably my second actually. Someone pointed out to me that there was this thing called Conway's Game of Life. You're probably familiar with it.

So there was a scientific American column by someone who did a monthly column about mathematical diversions and also blinking out on the guy's name. It was very famous at the time and I think up to the 90s or so. And one of his columns was about Conway's Game of Life and he had some illustrations and he wrote down all the rules and sort of there was the suggestion that this was philosophically interesting that that was why Conway had called it that And all I had was like the two pages photocopy of that article. I don't even remember where I got it. But it spoke to me and I remember implementing a version of that game for the batch computer we were using where I had a whole Pascal program that sort of read an initial situation from input and read some numbers that That said, do so many generations and print every so many generations. And then out would come pages and pages of sort of things.

Yeah. And I remember much later, I've done a similar thing using Python, but I'd sort of that original version I wrote at the time. I found interesting because I combined it with some trick I had learned during my electronics hobby as times. I essentially first on paper I designed a simple circuit built out of logic gates that took nine bits of input which is the sort of the cell and its neighbors. and produce the new value for that cell. And it's like a combination of a half-adder and some other clipping. No, it's actually a full-adder. And so I had worked that out. And then I translated that into a series of Boolean operations on Pascal integers, where you could use the integers as bitwise values. And so I could basically generate 60 bits of a generation in like eight instructions or so. Nice.

I think I went back and forth. As a student, we had an incredibly small budget of computer time that we could use. It was actually measured. I once got in trouble with one of my professors because I had overspend the department's budget. It's a different story. So I actually wanted the efficient implementation because I also wanted to explore what would happen with a larger number of generations and a larger sort of size of the board. And so once the implementation was flawless, I would feed a different patterns and then I think maybe there was a follow-up article where there were patterns that were like gliders, patterns that repeated themselves after a number of generations, but translated one or two positions to the right or something like that. And there were, I remember things like glider guns. Well, you can, you can Google Conway's game of life. It's still a, people still go on over it.

I'm not convinced that it's sort of a problem that lends itself to classic mathematical analysis.

There is a set of rules that doesn't essentially always just end up repeating itself in a trivial way.

I didn't really start reading science fiction until much much later. I think as a teenager, I read maybe one bundle of science fiction stories.

That's sort of the using computers to build something intelligent, always felt to me because I felt I had so much understanding of what actually goes on inside a computer. I knew how many bits of memory it had and how difficult it was to program and sort of I didn't believe at all that you could just build something intelligent out of that. That would really sort of satisfy my definition of intelligence. I think the most influential thing that I read in my early 20s was Goethele Escherbach. That was about consciousness and that was a big eye opener. in some sense.

Oh, yeah. I mean, I totally believe that brains are computers in some sense. I mean, the rules they use to play by are pretty different from the rules we can sort of implement in our current hardware. But I don't believe in like a separate thing that infuses us with intelligence or consciousness or any of that. There's no soul. I've been an atheist probably. from when I was 10 years old, just by thinking a bit about math and the universe. Well, my parents were atheists. Now, I know that you could be in atheists and still believe that there is something sort of about intelligence or consciousness that cannot possibly emerge from a fixed set of rules. I am not in that camp. I totally see that sort of given how many millions of years evolution took its time. DNA is a particular machine that sort of encodes information and an unlimited amount of information in in chemical form and has figured out a way to replicate itself. I thought that that was maybe it's 300 million years ago, but I thought it was closer to half a billion years ago that that sort of originated and it hasn't really changed that the sort of the structure of the DNA hasn't changed ever since that is like our binary code that we're having hardware I mean the basic programming language hasn't changed but maybe the programming itself of his leadership, it happened to be a set of rules that was good enough to develop endless variability and sort of the idea of self-replicating molecules competing with each other for resources and one type eventually always taking over that happened before there were any fossils. So we don't know how that exactly happened, but I believe it's clear that that did happen.

Those are pretty sort of separate topics. My line of work working with programming does not involve anything that goes in the direction of developing intelligence or consciousness, but sort of privately as an avid reader of popular science writing, I have some thoughts which is mostly that I don't actually believe that consciousness is an all or nothing thing. I have a feeling that and I forget what I read that influence this but I feel that if you look at a cat or a dog or a mouse, they have some form of intelligence. If you look at a fish, it has some form of intelligence. That evolution just took a long time, but I feel that the evolution of more and more intelligence that led to the human form of intelligence follow the evolution of the senses, especially the visual sense. I mean, there is an enormous amount of processing that's needed to interpret a scene, and humans are still better at that than computers are. And I have a feeling that there is a sort of The reason that like mammals is in particular developed the levels of consciousness that they have and that eventually sort of go from intelligence to self-awareness and consciousness has to do with sort of being a robot that has very highly developed senses as a lot of rich sensory information coming in.

Yeah, so in as far as robots go, I think that the self-driving cars have the sort of the greatest opportunity of developing something like that because when I drive myself, I don't just pay attention to the rules of the road. I also look round and I get clues from that, oh, this is a shopping district. Oh, here's an old lady crossing the street. Oh, here is someone carrying a pile of mail. There's a mailbox. That's you. They're going across the street to reach that mailbox. And I slow down. And I don't even think about that. And so there is so much where you turn your observations into an understanding of what other consciousnesses are going to do or what other systems in the world are going to be. Oh, that tree is going to fall. Yeah, I see sort of I see much more I expect somehow that if anything is going to become conscious, it's going to be the self-driving car and not the network of a bazillion Computers at in a Google or Amazon data center that are all network together to do whatever they do.

Yeah, if you look at the dog, the dog clearly knows. I mean, I'm not the dog owner, my buddy. I have friends who have dogs. The dogs clearly know what the humans around them are going to do or at least they have a model of what those humans are going to do and they learn. Some dogs know when you're going out and they want to go out with you. They're sad when you leave alone. They cry. They're afraid because they were mistreated when they were younger. we don't assign sort of consciousness to dogs or at least not not all that much, but I also don't think they have none of that. So I think it's it's consciousness and intelligence are not all or nothing.

They weren't aware of the concepts of pattern matching. in the sense that we are aware of it now. They thought they had discovered incredible bits of mathematics like Newton's calculus. And their sort of idealism, their extension of what they could do with logic and math went along those lines. And they thought There's logic, there's like a bunch of rules and a bunch of input they didn't realize that how you recognize a face is not just a bunch of rules but it's a shit ton of data. Plus a circuit that's sort of interprets visual clues and the context and everything else. And somehow can massively parallel pattern match against stored rules. But if I see you tomorrow here in front of the Dropbox office, I might recognize you, even if I'm wearing a different shirt. Yeah. But if I see you tomorrow in a coffee shop in Belmont, I might have no idea that it was you or on the beach or whatever. I make those kind of mistakes myself all the time. I see someone that I only know as like, oh, this person is a colleague of my wife. And then I see them at the movies and I didn't recognize them.

I don't know what that means. I mean, yes, in the sense that there is no actual magic there, but there are enough layers of abstraction from the facts as they enter my eyes and my ears to the understanding of the scene that I don't think that AI has really covered enough of of that distance. It's like if you take a human body and you realize it's built out of atoms, well that is a useless reductionist view, right? The body is built out of organs, the organs are built out of cells, the cells are built out of proteins, the proteins are built out of amino acids, amino acids are built out of atoms, and then you got to quantum mechanics.

That makes it sound so easy. I don't know who Sam Harris is.

Right. And the same about taking facts as our sensory organs take them in, and turning that into reasons and actions. There are a lot of abstractions that we haven't quite figured out how to deal with those. I didn't know if I can go on a tangent or not. So if I take a simple program that parses, say, say, have a compiler, it parses a program. In a sense, the input routine of that compiler of that parser is a sensing organ and it builds up a mighty complicated internal representation of the program and just saw it doesn't just have a linear sequence of bytes representing the text of the program anymore. It has an abstract syntax to me and I don't know how many of your viewers or listeners are familiar with compiler technology, but there is fewer and fewer these days. That's also true probably. People want to take a shortcut, but there's sort of this abstraction is a data structure that the compiler then uses to produce outputs that is relevant like a translation of that program to machine code that can be executed by hardware. And then the data structure gets thrown away. when a fish or a fly sees sort of gets visual impulses. I'm sure it also builds up some data structure and for the fly that may be very minimal, a fly may have only a few. I mean, in the case of a fly's brain, I could imagine that there are few enough layers of abstraction that it's not much more than when it's darker here than it is here. Well, it can sense motion because a fly sort of responds when you move your arm towards it. So clearly, its visual processing is intelligent, well, not intelligent, but it has an abstraction for motion. And we still have similar things in, but much more complicated in our brains. I mean, otherwise you couldn't drive a car if you couldn't, so if you didn't have an incredibly good abstraction for motion.

We built much more complicated data structures based on that. And we build more persistent data structures, sort of after some processing, some information, sort of get stored in our memory pretty much permanently and is available on recall. I mean, there are some things that you sort of your conscious that you're remembering it. Like, you give me your phone number. I, well, at my age, I have to write it down, but I could imagine I could remember those seven numbers or ten digits and reproduce them in a while if I sort of repeat them to myself a few times. So that's a fairly conscious form of memorization. On the other hand, how do I recognize your face? I have no idea. My brain has a whole bunch of specialized hardware that knows how to recognize faces. I don't know how much of that is sort of coded in our DNA and how much of that is trained over and over between the ages of zero and three. But somehow, our brains know how to do lots of things like that that are useful in our interactions with other humans, without really being conscious of how it's done anymore.

Well, didn't the cart also have the notion though that the soul and body were fundamentally separate?

I think in some point the higher levels of abstraction will not be called programming and they will not resemble what we call programming at the moment. There will not be source code. I mean, there will still be source code sort of at a lower level of the machine, just like there are still molecules and electrons and sort of proteins in our brains. And so there are still programming and system administration and who knows what's keeping to keep the machine running. But what the machine does is is a different level of abstraction in its sense. And as far as I understand the way that for last decade or more people have made progress with things like facial recognition or the self-driving cars is all by endless, endless amounts of training data where at least as a as a layperson and I feel myself totally as a layperson in that field it looks like the researchers who published the results don't necessarily know exactly how how their algorithms work and I often get upset when I sort of read a sort of a fluff piece about Facebook in the newspaper or social networks, and they say, well, algorithms. And that's like a totally different interpretation of the word algorithm. Because for me, the way I was trained or what I learned when I was eight or ten years old, an algorithm is a set of rules that you completely understand that can be mathematically analyzed and you can prove things. You can prove that airs dosenies, sieve produces all prime numbers and only prime numbers.

Well, there would be programming 2.0, 2.0, 2.0, 2.0, 2.0, 2.0. I wouldn't call that programming. It's just a different activity, just like building organs out of cells is not called chemistry.

Well, the question is probably only being asked because we don't quite know what that software 2 pointer actually is. And it sort of, I think there is a trueism that every task that AI has tackled in the past at some point we realized how it was done and then it was no longer considered part of artificial intelligence because it was no longer necessary to use that term. It was just, oh now we know how to do this. and a new field of science or engineering has been developed. And I don't know if sort of every form of learning or sort of controlling computer systems should always be called programming. I said, I don't know, maybe I'm focused too much on the terminology. But I expect that that there just will be different concepts where people with sort of different education and a different model of what they're trying to do will develop those concepts.

Programming 1.0 is actually sort of getting to that point too, where the sort of the ideal of a bug-free program has been abandoned long ago by most software developers. We only care about bugs that manifest themselves often enough to be annoying And we're willing to take the occasional crash or outage or incorrect result for granted because we can't possibly, we don't have enough programmers to make all the code bug free and it would be an incredibly tedious business. And if you try to throw formal methods at it, it becomes even more tedious. everyone's in a while the user clicks on a link in and somehow they get an error and the average user doesn't panic they just click again and see if it works better the second time which often magically it does or they go up and they try some other way of performing their task so That's sort of an end to end recovery mechanism. And inside systems, there is all sorts of retries and time outs and fallbacks. And I imagine that that sort of biological systems are even more full of that because otherwise they wouldn't survive.

In sort of basic programming education, the programs you're having students write are so small and simple. that if there is a bug you can always find it and fix it because the sort of programming as it's being taught in some even elementary middle schools in high school introduction to programming classes in college typically it's programming in the small very few classes sort of actually teach software engineering building large systems I mean Every summer here at Dropbox, we have a large number of interns. Every tech company on the West Coast has the same thing. These interns are always amazed because this is the first time in their life that they see what goes on in a really large software development environment. And everything they've learned in college was almost always about a much smaller scale. And somehow that difference in scale makes a qualitative difference in how you do things and how you think about it.

I was actually always caught by surprise. Yeah, pretty much every stage of computing.

That's where I got all the good stuff.

Well, I'm glad it wasn't aware of all the itches because I would probably not have been able to do anything. I mean, if you're trying to solve every problem at once, You saw nothing. Well, yeah, it's, it's too overwhelming. And so I had a very, very focused problem. I wanted a programming language that set somewhere in between shell scripting and C. And now, arguably, there is like one is higher level, one is lower level. And Python is sort of a language of an intermediate level, although it's still pretty much at the high level. I was thinking about much more about, I want a tool that I can use to be more productive as a programmer in a very specific environment. and I also had given myself a time budget for the development of the tool and that was sort of about three months for both the design like thinking through what are all the features of the language syntactically and semantically and how do I implement the whole pipeline from parsing the source code to executing it.

There are different tasks. And as a programmer, it's useful to have different tools available that are suitable for different tasks. So I still write C code. I still write shell code. But I write most of my things in Python. Why do I still use those other languages? Because sometimes the task just demands it. And well, I would say most of the time the task actually demands a certain language because the task is not right to program that solves problem x from scratch, but it's more like fix a bug in existing program x or add a small feature to an existing large program. But even if you sort of If you're not constrained in your choice of language by context like that, there is still the fact that if you write it in a certain language, then you have this balance between how long does it take you to write the code and how long does the code run? And when you're in sort of in the phase of exploring solutions, you often spend much more time writing the code than running it because every time you've sort of you've run it, you see that the output is not quite what you wanted and you spend some more time coding. and a language like Python just makes that iteration much faster because there are fewer details. There is a large library sort of there are fewer details that that you have to get right before your program compiles and runs. There are libraries that do all sorts of stuff for you so you can sort of very quickly take a bunch of existing components, put them together and get your prototype application running. Just like when I was building electronics, I was using a breadboard most of the time. So I had this like sprawled out circuit that If you shook it, it would stop working because it was not put together very well, but it functioned and all I wanted was to see that it worked and then move on to the next schematic or design or add something to it. Once you've figured out, oh, this is the perfect design for my radio or light sensor or whatever, then you can say, okay, how do we design a PCB for this? How do we solder the components in a small space? How do we make it so that it is robust against say voltage fluctuations or mechanical disruption. I mean, I know nothing about that when it comes to designing electronics, but I know a lot about that when it comes to to writing code.

I set to myself, I don't want to have to design everything from scratch. I'm going to borrow features from other languages that I like.

Yeah. And so that's why if you're 17 years old and you want to sort of create a programming language, you're not going to be very successful at it. because you have no experience with other languages. Whereas I was in my, let's say, mid-30s, I had written parsers before, so I had worked on the implementation of ABC. I had spent years debating the design of ABC with its authors, with its designers. I had nothing to do with the design. It was designed fully as it ended up being implemented when I joined the team. You borrow ideas and concepts and very concrete sort of local rules from different languages like the indentation and certain other syntactic features from ABC, but I chose to borrow string literals and how numbers work from C and various other things.

Well, yeah, so it was a group process, really. At that point, even though I was BDFL in nine, a name and certainly everybody respected my position as the creator and the current sort of owner of the language design. I was looking at everyone else for feedback. Sort of Python 3.0 in some sense was sparked by other people in the community pointing out, oh well there are a few issues that sort of bite users over and over. Can we do something about that? And for Python 3, we took a number of those Python words as they were called at the time. And we said, can we try to sort of make small changes to the language that address those words? And we had sort of, in the past, we had always taken backwards compatibility very seriously. And so many Python words in earlier versions had already been resolved because they could be resolved while maintaining backwards compatibility or sort of using a very gradual path of evolution of the language in a certain area. And so we were stuck with a number of words that were widely recognized as problems, not like roadblocks, but nevertheless sort of things that some people trip over and you know that That's always the same thing that people trip over when they trip. And we could not think of a backwards compatible way of resolving those issues.

And so, yes, for a long time, we had sort of resigned ourselves to, well, okay, the link, which is not going to be perfect in this way. And that's the way. And we sort of, certain of these, I mean, there are still plenty of things where you can say, well, that's That particular detail is better in Java or in our or in visual basic or whatever. And we're okay with that because well, we can't easily change it. It's not too bad. We can do a little bit with user education or we can have static analyzer or warnings in the parse or something. There were things where we thought, well, these are really problems that are not going away. They are getting worse in the future. We should do something about it.

Well, the toughest decision was probably to resign.

I'm glad you liked the writing because it was actually written pretty quickly. It was literally something like, after months and months of going around in circles, I had finally approved Pep 572, which I had a big hand in its design, although I didn't initiate it originally. I sort of gave it a bunch of nudges in a direction that would be better for the language.

No. That's the one or no. No. Pep 572 was actually a small feature which is assignment expressions. Oh, assignment expressions. Okay. That had been thought there was just a lot of debate where a lot of people claimed that they knew what was pithonic and what was not pithonic and they knew that this was going to destroy the language this was like a violation of pithons most fundamental design philosophy and I thought there was all bullshit because I was in favor of it and I would think I know something about pithons design philosophy so I was really tired and also stressed of that thing and literally after sort of announcing I was going to accept it a certain Wednesday evening I had finally sent the email it's accepted now let's just go implement it so I went to bed feeling really relieved that's behind me and I wake up Thursday morning 7 am and I think Well, that was the last one that's going to be such a terrible debate and that's a going to be said. That's the last time that I let myself be so stressed out about a pep decision. I should just resign. I've been thinking about retirement for half a decade. I've been joking and sort of mentioning retirement sort of telling the community some points in the future. I'm going to retire. Don't take the FL part of my title to literally. And I thought, OK, this is it. I'm done. I had the day off. I wanted to have a good time with my wife. We were going to a little beach down here by. And in I think maybe 15, 20 minutes. I wrote that thing that you just called Shakespearean. And the funny thing is, I didn't get so much crap for calling a Shakespearean. I didn't even realize what a monumental decision it was. Because five minutes later, I read that link to my message back on Twitter, where people were already discussing on Twitter, Guido resigned as the BDFL. And I had posted it on an internal forum that I thought was only read by core developers. So I thought I would at least have one day before it news would sort of get out.

Well, the whole segment wars are sort of a favorite activity in the programming community.

Well, if everybody is batting each other on the back and never telling the truth. Yes. It would not be a good thing. I think there is a middle ground where sort of being nasty to each other is not okay, but there is a middle ground where there is healthy ongoing criticism and feedback that is very productive. And at every level you see that, I mean, someone proposes to fix a very small issue in a code base. Chances are that some reviewer will sort of respond by saying, well, actually you can do it better the other way. When it comes to deciding on the future of the Python core developer community, we now have, I think, five or six competing proposals for a constitution.

I'm very confident about that future. By and large, I think that the debate has been very healthy and productive. And I actually, when I wrote that resignation, email, I knew that Python was in a very good spot and that the Python court development community, that the group of 50 or 100 people who sort of right or review most of the code that goes into Python. Those people get along very well most of the time a large number of different areas of expertise are represented different levels of experience in the Python Core Dev community, different levels of experience, completely outside it in software development in general, large systems, small systems, embedded systems. So I felt okay resigning because I knew that the community can really take care of itself.

Well, let's take the gill and paralyzation and asyncio as one topic. I'm not that hopeful that Python will develop into a sort of high concurrency, high parallelism language. That's sort of the way the language is designed, the way most users use the language, the way the language is implemented, all make that a pretty unlikely future.

I think asyncio is a special case because it sort of allows overlapping IO and only IO. And that is a sort of best practice of supporting very high throughput IO many connections per second. I'm not worried about that. I think Asyncio will evolve. There are a couple of competing packages. We have some very smart people who are sort of pushing us in sort of to make Asyncio better. Parallel computing. I think that Python is not the language for that. There are ways to work around it. But you can't expect to write an algorithm in Python and have a compiler automatically paralyzed that. What you can do is use a package like NumPy and a bunch of other very powerful packages that sort of Use all the CPUs available because you tell the package. Here's the data. Here's the abstract operation to apply over and go at it and then we're back in the C++ world. But those packages are themselves implemented usually in C++.

Yeah, my, it packaging has always been my least favorite topic. It's, it's, it's a really tough problem because the OS and the platform want to own packaging. But their packaging solution is not specific to a language. Like if you take Linux, there are two competing packaging solutions for Linux or for Unix in general. But they all work across all languages. and several languages like Node, JavaScript, and Ruby and Python all have their own packaging solutions that only work within the ecosystem of that language. Well, what should you use? That is a tough problem. My own approach is I use the system Packaging system to install Python and I use the Python packaging system then to install third party Python packages. That's what most people do. Ten years ago, Python packaging was really a terrible situation. Nowadays, PIP is the future. There is a separate ecosystem for numerical and scientific Python based on Anaconda. Those two can live together. I don't think there is a need for more than that.

Well, I would say that Python is definitely the best thing I've ever done. And I wouldn't say just the creation of Python, but the way I sort of raised by them, like a baby. I didn't just conceive a child, but I raised a child. And now I'm setting the child free in the world, and I've set up the child to sort of be able to take care of himself. And I'm very proud of that.

Oh, you can always play me the parents. The dead parent sketch.

It's pushing up the daisies.

Bless you. It's been a great conversation.